1. Field of the Invention
The present invention relates generally to the field of self-contained breathing apparatus, of the type wherein an air cylinder is supported by a bracket or mounting plate attached to a wall within a fire house or the quarters of a rescue squad, or to a wall of a fire truck or rescue squad vehicle. A bracket of this type commonly utilizes forwardly projecting spring clamp arms, releasably engaging an air cylinder pre-attached to a harness worn by the user. The air cylinder is supported by the harness upon one's back, so that when the firefighter or rescue squad member walks away from the bracket, the clamp arms are sprung apart to release the air cylinder.
2. Description of the Prior Art
Heretofore, mounting brackets or support plates for SCBA air cylinders have been very well known, and commonly employ a vertically extending, generally flat backplate, from which upper and lower pairs of clamp arms extend to releasably engage the supported air cylinder. Examples of such arrangements will be seen, for instance, in patents such as Ziaylek Design Patents U.S. Pat. No. Des. 222,527 issued Nov. 2, 1971; and U.S. Pat. No. Des. 237,357 issued Oct. 28, 1975.
These and other brackets or mounting plates designed for quick release of a supported SCBA air cylinder were designed for use with SCBA cylinders of an older type, manufactured of heavy steel. An empty steel cylinder for 30-minutes-use generally weighs about 19 lbs. The air and cylinder valve add about four more pounds, bringing the total weight of a typical SCBA utilizing a steel cylinder to approximately 33 lbs. Aluminum cylinders were introduced in 1974 or thereabouts, in an early attempt to reduce the total weight of the SCBA.
The cylinder resulting from this development itself weighed about 17 lbs. The resultant reduction in weight was not impressive. Accordingly, more recently an air cylinder known as a composite cylinder has been developed. That which has proved to be the strongest and most durable is in the form of a relatively lightweight, seamless aluminum liner, about which many layers of high strength glass fiber filaments are wound. The filaments are impregnated with epoxy resin, and include layers wrapped longitudinally of the metal shell. Thereafter, they further include helical wrappings.
The composite cylinder resulting from this arrangement is strongly reinforced, and yet the total weight is only half that of a steel cylinder.
The problem with this important development in SCBA air cylinders lies in the delicacy of the windings. The mere act of pressing a cylinder into a supported position upon the mounting bracket involves contact with the clamp arms adjacent the distal extremities thereof. Such contact often results in severing of some of the glass fiber filaments, especially when the clamp arms may be canted slightly, to an extent where the edges thereof may exert a cutting action on the glass fibers.
When the user dons the SCBA and walks away from the mounting bracket, pulling the air cylinder free, a further tendency to cut the fibers manifests itself. When this happens, the windings become loose and the cylinder loses its strength.
In such an event, the cylinder must be taken out of service, and rewound at substantial expense. It becomes important, accordingly, to consider means for eliminating or at least materially reducing the tendency of damage to the composite cylinder resulting from insertion in or removal from the clamp arms of a mounting bracket. So far as is known, however, no such means has yet been devised, that will produce this desirable result, and at the same time will maintain the required capability of the clamp arms for tightly gripping the air cylinder while it is not in use, and yet releasing the cylinder instantly in an emergency situation.